Residents, experts fear cap over toxic chemicals won't hold up

Three years ago this week, crews capped and sealed two pits of paper mill sludge that had long poisoned the San Jacinto River - a $9 million effort that brought some comfort to those who live near these murky waters.

The remedy has worked, holding the toxic sludge in place and out of the river. Yet public confidence is eroding, with some east Harris County residents and local officials calling for the removal of the harmful bisque of long-lived chemicals from the pits.

Their position gained some traction last week with a new analysis that found the site - one of the most polluted places in Texas - is in a bad spot for repeated flooding. Floods are increasingly likely because of more frequent storms, rising seas and subsidence, a condition caused by the sinking of soft soils, the analysis found.

Those natural forces could weaken the waste pits' structural integrity, allowing cancer-causing dioxins to escape into the environment, said Samuel Brody, the study's lead author and director of the Center for Texas Beaches and Shores at Texas A&M University at Galveston.

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Brody said the risk is too high to leave the dioxin-laced sediment in place. Unless federal regulators require its removal, "they are setting themselves up for a potential disaster," he said.

The study comes as the Environmental Protection Agency considers a final cleanup plan for the site, which was added to the Superfund list six years ago. Those responsible for the mess say it should be left under the armored cap, which is designed to withstand flood events that have a 1 in 100 chance of occurring in any given year - what some refer to as a 100-year flood.

International Paper Co. and McGinnes Industrial Maintenance Corp. said the cap, which consists of polyethylene liners and some 60,000 tons of rocks, could be fortified to handle a 500-year flood.

But to remove the cap and dig up the polluted mud - a lengthy process that would occur in part during hurricane season - "could unnecessarily expose both humans and the environment to serious risk," the companies wrote recently to the EPA.

No safe levels

McGinnes owned and operated the pits in the 1960s, filling a 20-acre site on dry land with waste from a now-closed paper mill near the Washburn Tunnel. The company later became part of Houston-based Waste Management.

In the process to whiten paper, the mill produced large amounts of dioxins - compounds so toxic that scientists measure them in trillionths of a gram. The EPA says there is no safe level of exposure to the chemicals, which are known to cause cancer and disrupt reproductive and immune systems.

The San Jacinto began running through the pits in the early 1970s because of subsidence caused by the pumping of groundwater.

With the pits under water, dioxins spread into the river and started their climb through the food chain. Fish, crab and other creatures ingested poisoned sediment and stored the chemicals in their fat and organs, prompting the state to warn people about eating their catch from these waters.

Armored cap

Initially, the armored cap was intended to be temporary, a quick strike to prevent the toxic muck from churning back into the water and from spreading farther into Galveston Bay. The EPA said there is no sign of dioxin releases into the river since the pits were capped and sealed.

Now the companies want it to be permanent. But there are lingering doubts about its ability to hold up over time.

"The cap has gone a long way to reduce short-term risk," said Jennifer Ronk, an environmental scientist at the Houston Advanced Research Center. "But I'm just not sure we can count on the cap alone in the long term."

People who live near the site share this concern. Last December, members of the San Jacinto River Coalition, standing in front of the Houston headquarters of Waste Management, called on the companies to clean up the contaminated site permanently by removing all affected sediment from the river.

The concerns stem from a relatively minor storm - much less than a 100-year event - that washed away some rocks topping the pits. The companies repaired the damage and made structural upgrades recommended by the Army Corps of Engineers.

Ronk said she didn't think the companies or the Corps have adequately considered the potential impacts of a 20-foot storm surge - a criticism that echoes the A&M study.

The analysis found that a Category 3 hurricane striking Galveston Bay during high tide would send a 23-foot wall of water over the waste pits. That same water would wash over the pits again as the surge released back into the bay, a one-two punch that could degrade the cap's structural integrity.

Flooding risks

Brody, the researcher, said earlier studies of the site's flood risk relied on historical data and did not take into account changing conditions, such as rising seas and more frequent storms because of climate change. At the same time, population growth in the area will put more people at risk.

The risk will become greater in the future, Brody said, so the pits should be removed.

But the companies said it's too risky to remove the sediment because there's a 30 percent to 40 percent probability of a big storm or major flood during the 19-month excavation.

It's also not worth the expense, the companies said. That's because the cap will be able to withstand erosive forces and events, a Texas Tech University professor concluded last month - while removing the dioxin-laced sediment would cost the companies as much as $99 million.

"This is a unique situation where more spending will likely decrease the protectiveness and the efficacy of the remedy," the companies wrote in a June letter to the EPA.

Gary Miller, the EPA's project manager for the San Jacinto cleanup, said the agency is expected to decide on the final remedy by the end of the year.